Biased pawl



May 9, 1961 J'. P. WATSON 2,983,161

BIASED PAWL Original Filed May 6, 1958 5 1m JAMES P. WATSON. l INVENTOR.

HERZ/G a. JESSUP. y ATTORNEYS United States Patent BIASED PAWL 'James P.Watson, Inglewood, Calif. (59 Waterway Road,

Waterway Village, Jupiter, Fla.), assignor of one-half to Joe Davidson,South Gate, Calif.

6 Claims. (Cl. 74577) This application relates to pivotally balancedmembers, and more particularly such members as are used in steppingswitches and motors.

This invention relates to improvements in pivoted components of the typedisclosed in co-pending applications Serial No. 607,422 (now issued asPatent No. 2,866,109) and Serial No. 662,109, both filed in the name ofJames P. Watson. This application is a division of oopending UnitedStates patent application Serial No. 733,449 filed May 6, 1958, nowPatent No. 2,933,580 entitled Pivotally Balanced Members.

It is an object of this invention to provide an improved balanced pawlstructure.

It is a further object of this invention to provide a pawl structurewhich is easier and cheaper to manufacture and assemble and which hasincreased longevity as compared with prior art structures of thisgeneral type.

It is another object of this invention to provide a design for aresiliently biased pivoted pawl structure wherein a heavier spring wiremay he used without proportionate increase in biasing torque, therebypermitting use of stronger and longer lived spring components.

It is another object of this invention to provide a spring biased rotarybalanced pawl wherein the biasing spring is free to perform its rotarybias on the pawl without being required to absorb an axial force torestrain the pawl in place on its mounting pin.

'It is another object of this invention to provide a balanced, biasedpawl wherein consistent operation may be obtained without maintenance ofcritical structural tolerances.

In accordance with these and other objects which will become apparenthereinafter, preferred forms of the present invention will now bedescribed with reference to the accompanying drawings, wherein:

Fig. 1 is a perspective view illustrating the balanced pawl of thepresent invention;

Fig. 2 is a section taken on line 2-2 in Fig. 1; and

Fig. 3 is a section taken on line 3-3 in Fig. 1.

Referring now to Figs. 1-3, the balanced pawl of the present inventionwill now be described. This pawl .is generally of the type described insaid United States Patent 2,866,109, particularly at Figs. 11-14, and insaid Serial 662,109, particularly at Figs. 6-10. Reference to thesespecifications is hereby made for a fuller understanding of theenvironment in which the pawl shown in Figs. l-3 is employed.

Referring to these figures, 71 designates an arbor or pin forming abearing for a pawl 72. The bearing portion of the pin 71 is ensmalled asshown at 73 where it passes through a bore (not shown) in the pawl 72,leaving a head 74 which restrains the pawl 72 against axial movement onthe pin 71 in one direction. The pawl is prevented from moving axiallyin the other direction by hearing against a suitable mounting member(not shown) in which the pin 71 is mounted. The head 74 of the pin 71has a pair of axially spaced circumferential grooves 76 and 77. Adiametral slot or kerf 78 is also provided in the head, and the slot 78has a sloping floor or bottom 79 communicating between the grooves 76and 77.

A spring wire 81 engages the pin 71 and pawl 72 to rotatrvely bias thepawl, in the following manner. The central portion 82 of the wire 81resides in the slot 78 adjacent the floor 79 thereof, the respectiveends of the wire 81 are then wrapped around the pin 71 in the samerotative direction, residing in the respective circumferent1al grooves76 and 77. Thus, one end of the wire 81 emerges from the shallow end ofthe kerf or slot 78 and proceeds around the groove 76 as shown at 83through an arc of approximately 270 and then leaves the groove 76tangentially as shown at 84. The tip 86 of the wire is then engaged in anotch or pocket 87 formed in a lateral post '88 at one end of the pawl72. The notch or pocket 87 is in substantial alignment with thecircumferential groove 76 so that the spring wire 81 may proceeddirectly from the pin 71 to the pocket 87 without further bending. Thisobviates canting of the spring ends with consequent danger of chafing.

The opposite tip 91 of the wire 81-resides in a pocket or notch 92formed in a post 93 at the opposite end of the pawl 72, which facesoppositely from the pocket 87.

The pocket 92 is spaced transversely of the pocket 87 so as to lie insubstantial longitudinal alignment with the other circumferential groove77 from which the tip end 91 emerges. This end is thus likewiseprevented from canting and chafing.

That portion of the head 74 between the groove 77 and the pawl 72constitutm a flange 94 which serves to hold the pawl 72 against axialremoval from the pin 71.

The flange 94 obviates requiring the spring wire 81 to hold the pawl 72against axial removal from the pin 71, consequently decreasing theloading on the spring and eliminating chafing. The large wrap-around ofapproximately 270 provided for each end of the spring 81 perrnits theuse of heavier spring wire and also makes the positioning of the kerf 78much less critical than if the extensive wrap-around were not employed.

While the instant invention has been shown and described herein in whatis conceived to be the most practical and preferred embodiments, it isrecognized that departures may be made therefrom within the scope of theinvention which is therefore not to be limited to the details disclosedherein but is to be afforded the full scope of the claims.

What is claimed is:

l. Balanced pawl means comprising a pawl having first and second endportions, a pivot pin projecting through said pawl at the centerthereof, said pin having a pair of spaced circumferential grooves and adiametral slot communicating from one groove to the other, and a springwire having its central portion residing in said slot, the respectiveends of said spring each being wrapped in a respective one of saidgrooves in the same rotative direction through an arc of substantiallymore than 180 and extending from the respective grooves in the directionof respective ones of said first and second end portions, the tips ofsaid spring Wire engaging the respective end portions of said pawl torotatively bias said pawl in a given rotative direction.

2. Pawl means in accordance with claim 1 wherein said pawl is providedwith pockets at each of said end portions thereof in which therespective ends of said wire reside.

3. Pawl means in accordance with claim 1 wherein said pawl is providedwith pockets at each of said end portions thereof in which therespective ends of said Wire reside and wherein said pockets are spacedlongitudinally and transversely of one another and lying in substantiallongitudinal alignment with the respective grooves from which the wireends extend, thereby to obviate canting ofhhiid springendswitWcbnsequentchafing thereof."

4. Pawl means in accordance With claim 1 wherein said spring wireresides in the respective circumferential grooves through an arc of atleast approximately 270. 5. Pawl means in accordance with claiml'wherein that portion of the pivot pin passing through said pawl isensmalled leaving a flange on said pin' adjacent said pawl whichinhibits axial movement of said'pawl along said pin in one direction.

6. Balanced pawl means compn'sing an elongated pawl having first andsecond end portions with pockets formed in each of said end portions, apivot pin projecting through said pawl at the center thereof whereinthat portion of the pivot in passing throughsaid pawl is of a reduceddiameter forming a shoulder on said pin adjacent said pawl whichinhibits axial movement of said pawl along said pin in one direction,said pin having a pair of spaced circumferential grooves and having adiametral slot communicating from one -groove to the other, and a springwire having its centrahportion residing in said diametral slot, therespective ends of said spring each being wrapped in a respective one ofsaid grooves in the same rotative direction through an arc of at leastapproximately 270 degrees, the tips of said spring wire residing inrespective ones of said pockets to respectively bias said pawl in agiven rotative direction, said pockets being spaced longitudinally andtransversely of one another and lying in substantial longitudinalalignment with the respective grooves from which thewire ends extend,thereby to obviate canting of said spring ends withcon'sequent chafingthereof.

References Cited in the file of this patent UNITED STATES PATENTSBennett May 15, 1945

